The present invention relates to improvements in and relating to a walking beam of the type used in the manufacturing and processing lines of steel pipe, round bars or the like for transferring the material.
Where various kinds of steel products such as steel pipes or round bars are to be transferred transversely, particularly in a hot line such as a heating furnace where the occurrence of defects, e.g., scoring must be avoided, a walking beam is used for transversally transferring steel products. This walking beam comprises a plurality of stationary beams and a plurality of transfer beams which are arranged parallel to one another and the transfer beams are caused to make a circular motion by means of link mechanisms in a manner that a steel product placed on the stationary beams is raised from below, moved forward and placed again on the stationary beams by the transfer beams and this process is repeated by the circular motion of the transfer beams to effect the transversal transfer of the steel material. In the case of an ordinary walking beam, a plurality of transfer beams are caused to make a circular motion vertically with a predetermined radius and this radius of circular motion determines the feed length of the steel product transfer stroke. Usually, when it is desired to change the feed length of the transfer stroke, it is necessary to rearrange the link mechanisms which cause the transfer beams to make a circular motion and this not only involves complicated operations for rearranging purposes but also a disadvantage of making it necessary to stop the transfer line during the period of rearrangement.
In the case of a walking beam of the type in which its transfer beams are driven by hydraulic mechanisms, while the transfer length can be varied by varying the stroke of the hydraulic cylinders, there are many disadvantages that it is difficult to stop accurately the hydraulic cylinders in the middle of their strokes, that the transfer speed is limited by the speed of the hydraulic cylinders making the walking beam unfit for high-speed transferring purposes and so on.